RHEL 8 : ldns (RHSA-2026:49520)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Red Hat Security Advisory RHSA-2026:49520. The text
# itself is copyright (C) Red Hat, Inc.
##

include('compat.inc');

if (description)
{
  script_id(331700);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/03");

  script_cve_id("CVE-2026-10846");
  script_xref(name:"RHSA", value:"2026:49520");

  script_name(english:"RHEL 8 : ldns (RHSA-2026:49520)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Red Hat host is missing a security update for ldns.");
  script_set_attribute(attribute:"description", value:
"The remote Redhat Enterprise Linux 8 host has packages installed that are affected by a vulnerability as referenced in
the RHSA-2026:49520 advisory.

    The ldns packages contain a library with the aim to simplify DNS programming in C. All low-level
    DNS/DNSSEC operations are supported. We also define a higher level API which allows a programmer to (for
    instance) create or sign packets.

    Security Fix(es):

    * ldns: ldns: Off-path poisoning attacks due to insufficient query-response matching (CVE-2026-10846)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and
    other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/updates/classification/#important");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2487437");
  # https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_49520.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?7052d0c2");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:49520");
  script_set_attribute(attribute:"solution", value:
"Update the RHEL ldns package based on the guidance in RHSA-2026:49520.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:C/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-10846");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(940);
  script_set_attribute(attribute:"vendor_severity", value:"Important");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/06/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/03");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/03");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:8");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:rhel_eus:8.10");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:ldns");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:ldns-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:ldns-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:ldns-utils");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:perl-ldns");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:python3-ldns");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Red Hat Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl", "redhat_repos.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/cpu");

  exit(0);
}


include('rpm2.inc');
include('rhel.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_product = get_kb_item('installed_os/local/SSH/0/product');
if (isnull(os_product) || 'Red Hat' >!< os_product) audit(AUDIT_OS_NOT, 'Red Hat');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'Red Hat');
if (!rhel_check_release(operator: 'ge', os_version: os_version, rhel_version: '8')) audit(AUDIT_OS_NOT, 'Red Hat 8.x', 'Red Hat ' + os_version);

if (!get_kb_item('Host/RedHat/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu && 'ppc' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Red Hat', cpu);

var constraints = [
  {
    'release': '8',
    'repo_relative_urls': [
      'content/dist/rhel8/8.10/aarch64/appstream/debug',
      'content/dist/rhel8/8.10/aarch64/appstream/os',
      'content/dist/rhel8/8.10/aarch64/appstream/source/SRPMS',
      'content/dist/rhel8/8.10/ppc64le/appstream/debug',
      'content/dist/rhel8/8.10/ppc64le/appstream/os',
      'content/dist/rhel8/8.10/ppc64le/appstream/source/SRPMS',
      'content/dist/rhel8/8.10/s390x/appstream/debug',
      'content/dist/rhel8/8.10/s390x/appstream/os',
      'content/dist/rhel8/8.10/s390x/appstream/source/SRPMS',
      'content/dist/rhel8/8.10/x86_64/appstream/debug',
      'content/dist/rhel8/8.10/x86_64/appstream/os',
      'content/dist/rhel8/8.10/x86_64/appstream/source/SRPMS',
      'content/dist/rhel8/8.6/aarch64/appstream/debug',
      'content/dist/rhel8/8.6/aarch64/appstream/os',
      'content/dist/rhel8/8.6/aarch64/appstream/source/SRPMS',
      'content/dist/rhel8/8.6/ppc64le/appstream/debug',
      'content/dist/rhel8/8.6/ppc64le/appstream/os',
      'content/dist/rhel8/8.6/ppc64le/appstream/source/SRPMS',
      'content/dist/rhel8/8.6/s390x/appstream/debug',
      'content/dist/rhel8/8.6/s390x/appstream/os',
      'content/dist/rhel8/8.6/s390x/appstream/source/SRPMS',
      'content/dist/rhel8/8.6/x86_64/appstream/debug',
      'content/dist/rhel8/8.6/x86_64/appstream/os',
      'content/dist/rhel8/8.6/x86_64/appstream/source/SRPMS',
      'content/dist/rhel8/8.8/aarch64/appstream/debug',
      'content/dist/rhel8/8.8/aarch64/appstream/os',
      'content/dist/rhel8/8.8/aarch64/appstream/source/SRPMS',
      'content/dist/rhel8/8.8/ppc64le/appstream/debug',
      'content/dist/rhel8/8.8/ppc64le/appstream/os',
      'content/dist/rhel8/8.8/ppc64le/appstream/source/SRPMS',
      'content/dist/rhel8/8.8/s390x/appstream/debug',
      'content/dist/rhel8/8.8/s390x/appstream/os',
      'content/dist/rhel8/8.8/s390x/appstream/source/SRPMS',
      'content/dist/rhel8/8.8/x86_64/appstream/debug',
      'content/dist/rhel8/8.8/x86_64/appstream/os',
      'content/dist/rhel8/8.8/x86_64/appstream/source/SRPMS',
      'content/dist/rhel8/8.9/aarch64/appstream/debug',
      'content/dist/rhel8/8.9/aarch64/appstream/os',
      'content/dist/rhel8/8.9/aarch64/appstream/source/SRPMS',
      'content/dist/rhel8/8.9/ppc64le/appstream/debug',
      'content/dist/rhel8/8.9/ppc64le/appstream/os',
      'content/dist/rhel8/8.9/ppc64le/appstream/source/SRPMS',
      'content/dist/rhel8/8.9/s390x/appstream/debug',
      'content/dist/rhel8/8.9/s390x/appstream/os',
      'content/dist/rhel8/8.9/s390x/appstream/source/SRPMS',
      'content/dist/rhel8/8.9/x86_64/appstream/debug',
      'content/dist/rhel8/8.9/x86_64/appstream/os',
      'content/dist/rhel8/8.9/x86_64/appstream/source/SRPMS',
      'content/dist/rhel8/8/aarch64/appstream/debug',
      'content/dist/rhel8/8/aarch64/appstream/os',
      'content/dist/rhel8/8/aarch64/appstream/source/SRPMS',
      'content/dist/rhel8/8/ppc64le/appstream/debug',
      'content/dist/rhel8/8/ppc64le/appstream/os',
      'content/dist/rhel8/8/ppc64le/appstream/source/SRPMS',
      'content/dist/rhel8/8/s390x/appstream/debug',
      'content/dist/rhel8/8/s390x/appstream/os',
      'content/dist/rhel8/8/s390x/appstream/source/SRPMS',
      'content/dist/rhel8/8/x86_64/appstream/debug',
      'content/dist/rhel8/8/x86_64/appstream/os',
      'content/dist/rhel8/8/x86_64/appstream/source/SRPMS',
      'content/e6s/rhel8/8.10/aarch64/appstream/debug',
      'content/e6s/rhel8/8.10/aarch64/appstream/os',
      'content/e6s/rhel8/8.10/aarch64/appstream/source/SRPMS',
      'content/e6s/rhel8/8.10/ppc64le/appstream/debug',
      'content/e6s/rhel8/8.10/ppc64le/appstream/os',
      'content/e6s/rhel8/8.10/ppc64le/appstream/source/SRPMS',
      'content/e6s/rhel8/8.10/s390x/appstream/debug',
      'content/e6s/rhel8/8.10/s390x/appstream/os',
      'content/e6s/rhel8/8.10/s390x/appstream/source/SRPMS',
      'content/e6s/rhel8/8.10/x86_64/appstream/debug',
      'content/e6s/rhel8/8.10/x86_64/appstream/os',
      'content/e6s/rhel8/8.10/x86_64/appstream/source/SRPMS',
      'content/public/ubi/dist/ubi8/8/aarch64/appstream/debug',
      'content/public/ubi/dist/ubi8/8/aarch64/appstream/os',
      'content/public/ubi/dist/ubi8/8/aarch64/appstream/source/SRPMS',
      'content/public/ubi/dist/ubi8/8/ppc64le/appstream/debug',
      'content/public/ubi/dist/ubi8/8/ppc64le/appstream/os',
      'content/public/ubi/dist/ubi8/8/ppc64le/appstream/source/SRPMS',
      'content/public/ubi/dist/ubi8/8/s390x/appstream/debug',
      'content/public/ubi/dist/ubi8/8/s390x/appstream/os',
      'content/public/ubi/dist/ubi8/8/s390x/appstream/source/SRPMS',
      'content/public/ubi/dist/ubi8/8/x86_64/appstream/debug',
      'content/public/ubi/dist/ubi8/8/x86_64/appstream/os',
      'content/public/ubi/dist/ubi8/8/x86_64/appstream/source/SRPMS'
    ],
    'pkgs': [
      {'reference':'ldns-1.7.0-23.el8_10', 'rpm_spec_vers_cmp':TRUE}
    ]
  },
  {
    'release': '8',
    'repo_relative_urls': [
      'content/dist/rhel8/8.10/aarch64/codeready-builder/debug',
      'content/dist/rhel8/8.10/aarch64/codeready-builder/os',
      'content/dist/rhel8/8.10/aarch64/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.10/ppc64le/codeready-builder/debug',
      'content/dist/rhel8/8.10/ppc64le/codeready-builder/os',
      'content/dist/rhel8/8.10/ppc64le/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.10/s390x/codeready-builder/debug',
      'content/dist/rhel8/8.10/s390x/codeready-builder/os',
      'content/dist/rhel8/8.10/s390x/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.10/x86_64/codeready-builder/debug',
      'content/dist/rhel8/8.10/x86_64/codeready-builder/os',
      'content/dist/rhel8/8.10/x86_64/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.6/aarch64/codeready-builder/debug',
      'content/dist/rhel8/8.6/aarch64/codeready-builder/os',
      'content/dist/rhel8/8.6/aarch64/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.6/ppc64le/codeready-builder/debug',
      'content/dist/rhel8/8.6/ppc64le/codeready-builder/os',
      'content/dist/rhel8/8.6/ppc64le/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.6/s390x/codeready-builder/debug',
      'content/dist/rhel8/8.6/s390x/codeready-builder/os',
      'content/dist/rhel8/8.6/s390x/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.6/x86_64/codeready-builder/debug',
      'content/dist/rhel8/8.6/x86_64/codeready-builder/os',
      'content/dist/rhel8/8.6/x86_64/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.8/aarch64/codeready-builder/debug',
      'content/dist/rhel8/8.8/aarch64/codeready-builder/os',
      'content/dist/rhel8/8.8/aarch64/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.8/ppc64le/codeready-builder/debug',
      'content/dist/rhel8/8.8/ppc64le/codeready-builder/os',
      'content/dist/rhel8/8.8/ppc64le/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.8/s390x/codeready-builder/debug',
      'content/dist/rhel8/8.8/s390x/codeready-builder/os',
      'content/dist/rhel8/8.8/s390x/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.8/x86_64/codeready-builder/debug',
      'content/dist/rhel8/8.8/x86_64/codeready-builder/os',
      'content/dist/rhel8/8.8/x86_64/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.9/aarch64/codeready-builder/debug',
      'content/dist/rhel8/8.9/aarch64/codeready-builder/os',
      'content/dist/rhel8/8.9/aarch64/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.9/ppc64le/codeready-builder/debug',
      'content/dist/rhel8/8.9/ppc64le/codeready-builder/os',
      'content/dist/rhel8/8.9/ppc64le/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.9/s390x/codeready-builder/debug',
      'content/dist/rhel8/8.9/s390x/codeready-builder/os',
      'content/dist/rhel8/8.9/s390x/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8.9/x86_64/codeready-builder/debug',
      'content/dist/rhel8/8.9/x86_64/codeready-builder/os',
      'content/dist/rhel8/8.9/x86_64/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8/aarch64/codeready-builder/debug',
      'content/dist/rhel8/8/aarch64/codeready-builder/os',
      'content/dist/rhel8/8/aarch64/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8/ppc64le/codeready-builder/debug',
      'content/dist/rhel8/8/ppc64le/codeready-builder/os',
      'content/dist/rhel8/8/ppc64le/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8/s390x/codeready-builder/debug',
      'content/dist/rhel8/8/s390x/codeready-builder/os',
      'content/dist/rhel8/8/s390x/codeready-builder/source/SRPMS',
      'content/dist/rhel8/8/x86_64/codeready-builder/debug',
      'content/dist/rhel8/8/x86_64/codeready-builder/os',
      'content/dist/rhel8/8/x86_64/codeready-builder/source/SRPMS',
      'content/public/ubi/dist/ubi8/8/aarch64/codeready-builder/debug',
      'content/public/ubi/dist/ubi8/8/aarch64/codeready-builder/os',
      'content/public/ubi/dist/ubi8/8/aarch64/codeready-builder/source/SRPMS',
      'content/public/ubi/dist/ubi8/8/ppc64le/codeready-builder/debug',
      'content/public/ubi/dist/ubi8/8/ppc64le/codeready-builder/os',
      'content/public/ubi/dist/ubi8/8/ppc64le/codeready-builder/source/SRPMS',
      'content/public/ubi/dist/ubi8/8/s390x/codeready-builder/debug',
      'content/public/ubi/dist/ubi8/8/s390x/codeready-builder/os',
      'content/public/ubi/dist/ubi8/8/s390x/codeready-builder/source/SRPMS',
      'content/public/ubi/dist/ubi8/8/x86_64/codeready-builder/debug',
      'content/public/ubi/dist/ubi8/8/x86_64/codeready-builder/os',
      'content/public/ubi/dist/ubi8/8/x86_64/codeready-builder/source/SRPMS'
    ],
    'pkgs': [
      {'reference':'ldns-devel-1.7.0-23.el8_10', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'ldns-doc-1.7.0-23.el8_10', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'ldns-utils-1.7.0-23.el8_10', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'perl-ldns-1.7.0-23.el8_10', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python3-ldns-1.7.0-23.el8_10', 'rpm_spec_vers_cmp':TRUE}
    ]
  }
];

var applicable_repo_urls = rhel_determine_applicable_repository_urls(constraints:constraints);
if(applicable_repo_urls == RHEL_REPOS_NO_OVERLAP_MESSAGE) exit(0, RHEL_REPO_NOT_ENABLED);

var os_release = get_one_kb_item('installed_os/local/SSH/0/release');
var os_sp = get_one_kb_item('Host/*/minor_release');

var flag = 0;
var repo_relative_urls;
var reference;
var sp;
var _cpu;
var el_string;
var rpm_spec_vers_cmp;
var epoch;
var allowmaj;
var exists_check;
var cves;
foreach var constraint ( constraints ) {
  # Check that the target release is equal to the affected release
  if (!empty_or_null(constraint['release'])){
    if (constraint['release'] != os_release) continue;
  }
  if (!empty_or_null(constraint['sp'])){
    if (constraint['sp'] != os_sp) continue;
  }

  if (!empty_or_null(constraint['repo_relative_urls'])) repo_relative_urls = constraint['repo_relative_urls'];

  foreach var pkg ( constraint['pkgs'] ) {
    reference = NULL;
    sp = NULL;
    _cpu = NULL;
    el_string = NULL;
    rpm_spec_vers_cmp = NULL;
    epoch = NULL;
    allowmaj = NULL;
    exists_check = NULL;
    cves = NULL;
    if (!empty_or_null(pkg['reference'])) reference = pkg['reference'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['cpu'])) _cpu = pkg['cpu'];
    if (!empty_or_null(pkg['el_string'])) el_string = pkg['el_string'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['epoch'])) epoch = pkg['epoch'];
    if (!empty_or_null(pkg['allowmaj'])) allowmaj = pkg['allowmaj'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (reference &&
        rhel_decide_repo_relative_url_check(required_repo_url_list:repo_relative_urls) &&
        (applicable_repo_urls || (!exists_check || rpm_exists(rpm:exists_check))) &&
        rpm_check(sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj, cves:cves)) flag++;
  }
}

if (flag)
{
  var extra = NULL;
  if (isnull(applicable_repo_urls) || !applicable_repo_urls) extra = rpm_report_get() + redhat_report_repo_caveat();
  else extra = rpm_report_get();
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : extra
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'ldns / ldns-devel / ldns-doc / ldns-utils / perl-ldns / etc');
}